Frost-Damaged Banana Trees

Effects of Frost

• Cold air sinks, so the chillest temperatures occur closest to the ground. On nights expected to produce frost, leaves on taller banana plants may escape any frost damage sink they avoid the coldest, freezing air that pools around their stem bases. When subfreezing temperatures do reach the banana leaves, the extent of tissue rupture from sap freezing varies depending on the duration of the frost. A brief frost may cause leaf edges or tips to brown, while a longer bout with subfreezing conditions kills the entire leaf blade.

Response

• If a frost merely kills foliage, the banana continues to grow as long as subsequent temperatures remain above freezing. Continued frosts or prolonged freezes further kill tissues down the length of the banana's trunklike stem. If leaves are harmed and display brown edges, new leaves continue to emerge and unroll from the growing tip on the top of the stem. If the growing tip or stem is killed by frost, they are replaced by suckering shoots that later emerge from the underground rhizomes. Growth occurs more rapidly once air and soil temperatures don't remain colder than 70 degrees Fahrenheit.

Pruning Maintenance

• Frost damage on bananas may not immediately occur in the wake of a frost. Leaves may yellow or die several days later. Do not be eager to prune away frost-damaged leaves and stems, especially if it is still winter and more frosts may still occur. Removing leaves encourages new growth. You don't want new leaves or shoots to appear prematurely when additional frosts or freezes may still happen. Wait until early to mid spring to thoroughly trim and tidy up the banana plant: after the last expected frost date in your area.

Cold Hardiness

• Although with tropical origins, likely in Southeast Asia, bananas may be grown as summer annuals in cold winter regions, or their rhizomes dug up in fall to overwinter indoors. Even though frost and freezes kill above-ground parts of bananas, plants rejuvenate in spring as long as the underground roots are not frozen. Many types of bananas overwinter underground and resprout in spring's warmth in U.S. Department of Agriculture plant hardiness zones 7b and warmer. Not all bananas demonstrate the same ability to overwinter, but in zones 8 and 9, far more types overwinter successfully. In these regions, varying dieback from cold occurs, but waiting to prune dead plant tissues should always be delayed until the threat of frost ends in spring.